877 research outputs found

    Incidência da baixa fertilidade em touros no interior centro e sul de Portugal (Resultados de exames andrológicos em bovinos)

    Get PDF
    Só está disponível o resumo.A eficiência reprodutiva em bovinicultura é fundamental na viabilização económica das explorações. No atual quadro comunitário de apoios, esta eficiência é evidente, determinando o montante das ajudas a receber pelos produtores, que dependem da fertilidade dos bovinos. Entre janeiro de 2012 e setembro de 2015, foram avaliados através de exame andrológico, 223 touros reprodutores com idades compreendidas entre os 13 e 156 meses, em 35 explorações de carne, no interior centro e sul de Portugal. Cerca de 57% dos exames foram efetuados nos meses de setembro a dezembro, devido à maior procura deste serviço por parte dos produtores, para preparação da época de cobrições sequente. Foram avaliados touros das raças: Limousine, Charolês, Alentejana, Mertolenga e Cruzados. Foram aprovados 72,6% dos touros, reprovados 14,8% e recomendada a reavaliação a 12,6%. Para os parâmetros motilidade individual e massal, mais de 50% dos touros avaliados apresentam esperma de muito boa e de boa qualidade; 91% dos reprovados apresentam esperma de má qualidade. Em 95% dos touros aprovados, a condição corporal é adequada (≥5). Entre os reprovados, 15% apresentam condição corporal inadequada (≤4). Considerando duas classes de idade média, 36% dos touros aprovados, têm menos de 24 meses de idade. Entre os touros reprovados, apenas 6% apresenta idade inferior a 24 meses e 56% tem idade superior a 5 anos. Indicador do efeito da idade em sistemas de produção extensivos. De entre os touros classificados para reavaliação (n=28), apenas 12 foram reavaliados e destes, 50% foram reclassificados em aprovados. Em conclusão, 21% dos touros apresenta baixa a nula fertilidade e uma perda económica evidente, reforçada pela sua permanência em épocas de cobrição sucessivas. Os touros reprovados poderiam prejudicar a produção de cerca de 1155 vacas, induzindo uma perda de rendimento de cerca de 577 mil euros, nas 35 explorações abrangidas por este apoio técnico.info:eu-repo/semantics/publishedVersio

    Effect of chronic infusion of leptin and nutrition on sexual maturation of zebu heifers

    Get PDF
    The amount of fat in the carcass has been proposed as a regulator of initiation of puberty in cattle. To test if changes in energy intake and in circulating leptin concentration are each capable of altering age, BW, and body composition at puberty, 36 prepubertal Nellore heifers, 18 to 20 mo old, 275.8 ± 17.2kg BW, and BCS of 5 ± 0.5 (1 to 9 scale), were randomly assigned to each of 3 treatments (n = 12): High (high energy diet), Low (low energy diet), and LL [low energy diet + ovine leptin (oLeptin)]. Diets were formulated to promote BW gain of 0.4 kg/d (groups Low and LL) or 1.2 kg/d (High group). After 14 d of adjustment to diet, heifers in LL group received subcutaneous injections of oLeptin at 4.8 μg/kg BW twice a day for 56 d. Groups High and Low received similar injections of 2 mL saline solution. Age at puberty was considered to be the age on first detection of a corpus luteum, confirmed by plasma concentrations of progesterone of >1 ng/mL. Heifers were slaughtered on the second day after first corpus luteum detection. Expression of leptin gene was quantified by real-time PCR using ribosomal protein-L19 (RPL19) as a control gene. Leptin administration increased (P = 0.04) leptin serum concentration but had no effect (P > 0.05) on age, BW, or BCS at puberty. High energy intake increased (P < 0.01) leptin concentration, accelerated (P = 0.02) puberty, and increased (P < 0.01) BCS at puberty, without altering (P = 0.17) BW at puberty. High energy intake also accelerated (P = 0.04) follicular development. Leptin administration caused a significant (P < 0.05) but transient increase in follicular development, which was similar to the transient increase in leptin serum concentration. Results from leptin gene expression demonstrated that high energy intake increased (P < 0.01) and leptin administration decreased (P < 0.01) leptin expression in 3 adipose tissues. The observed decrease in leptin gene expression after administration of leptin could explain the reduction in leptin serum concentration after 30 d of treatment and consequently the failure of leptin to accelerate puberty. Our findings did not support the hypothesis that reduced serum concentration of leptin is an important hindrance for puberty onset in malnourished zebu heifers. Although exogenous administration of leptin temporarily enhanced rate of follicular growth, it did not accelerate puberty

    A PLL-based multirate structure for time-varying power systems harmonic/interharmonic estimation

    Get PDF
    This paper describes a phase-locked-loop (PLL)-based power systems harmonic estimation algorithm, which uses an analysis filter bank and multirate processing. The filter bank is composed of bandpass filters. The initial center frequency of each filter is purposely chosen to be equal to harmonic frequencies. However, an adaptation strategy makes it possible to track time-varying frequencies as well as interharmonic components. A downsampler device follows the filtering stage, reducing the computational burden, especially because undersampling operations are performed. Finally, the last stage is composed of a PLL estimator which provides estimates for amplitude, phase, and frequency of the input signal. The proposed method improves the accuracy, computational effort, and convergence time of the previous harmonic estimator based on cascade PLL configuration

    Evaluation of growth inhibitory activity of Crataegus monogyna Jacq. flower bud extracts against human tumor cell lines

    Get PDF
    The vast structural diversity of natural compounds found in plants provides unique opportunities for discovering new drugs with possible beneficial effects on human health, including regulation of proliferation and cell death pathways leading to cancer [1]. Crataegus monogyna Jacq. has been studied by our research group to confirm its different alleged health benefits [2-4]. Herein, the antiproliferative activity of phenolic extracts from C. monogyna flower buds was evaluated on four different human tumor cell lines: HeLa, cervical carcinoma; HepG2, hepatocellular carcinoma; MCF-7, breast adenocarcinoma; NCI-H460, non-small cell lung cancer. The antiproliferative activity was measured by calculating Gl50 values (50% of cell growth inhibition) for each cell line, according to the procedure adopted by the National Cancer Institute for in vitro anticancer drug screening, which uses sulforhodamine B assay to assess cell groW1h inhibition [5]. The obtained antiproliferative activity was very similar among the assayed cell lines: HeLa, Gl50 = 63.55±3.56 μg/ml; HepG2, Gl50 = 88.45±8.11 μg/ml; MCF7, Gl50 = 66.96±0.01 μg/ml ; NCI -H460, Gl50 = 67.61±4.29 μg/ml. The lower activity against HepG2 cells might be related with the type of proliferation of this cell line, the only one with a monolayer growth type among the assayed lines . The activity demonstrated by the phenolic extract of C. monogyna might be explained by their high amounts in flavonoids, which are known for modulating a variety of biological events associated with cancer progression and development, such as cell proliferation, apoptosis, cell differentiation and neovascularization [3]. Accordingly, C. monogyna may be considered as a source of important phytochemicals with bioactive properties to be explored for pharmaceutical applications

    Impact of methodological approaches in the agreement between subjective and objective methods for assessing screen time and sedentary behavior in pediatric population: a systematic review

    Get PDF
    Introduction: sedentary behavior is an important target for health promotion. In this systematic review, we aimed to provide evidence to support decisions about measurement approach choices for subjectively assessing sedentary behavior in pediatric population, adopting objective methods as the reference. Methods: in this systematic review with meta-analysis, published studies were retrieved from electronic databases: Medline (PubMed), Web of Science, Embase, SPORTDiscus, BioMed Central and SCOPUS. We considered studies evaluating sedentary behavior agreement through questionnaire and/or diary in comparison with an objective measure. A total of six inclusion criteria v, rere used. We synthesized the data using correlation coefficients (r) as an indicator of agreement estimates. The review protocol is registered in the PROSPERO database (CRD42014015138). Results: a total of 14 studies met the inclusion criteria with ages ranging from 3 to 17.5 years and provided 17 agreement analyses. Thirteen of these agreement analyses (76.5%) reported correlation coefficients. We found two major groups of sedentary activities: screen time (47.1%) and sedentary behaviors (52.9%). The pooled agreement between questionnaires and accelerometers for assessing self-reported screen time was negative (r =-0.15; Cl 95%:-0.17 to-0.13). Conversely, when the sedentary behavior was assessed by questionnaires and accelerometers, the pooled agreement, vas positive for parent-reporting (r = 0.09; Cl 95%; 0.04 to 0.13) and self-reporting (r = 0.43; CI 95%: 0.40 to 0.47) in children and adolescents, respectively. Conclusion: questionnaires have positive agreement with accelerometers for assessing sedentary behavior, whereas the agreement is negative for assessing screen time. Self-reported questionnaires are recommended methods to measure sedentary behavior in adolescents

    Behavioral and electroencephalographic analysis of seizures induced by intrahippocampal injection of granulitoxin, a neurotoxic peptide from the sea anemone Bunodosoma granulifera

    Get PDF
    In this study, the behavioral and electroencephalographic (EEG) analysis of seizures induced by the intrahippocampal injection in rats of granulitoxin, a neurotoxic peptide from the sea anemone Bunodosoma granulifera, was determined. The first alterations occurred during microinjection of granulitoxin (8 µg) into the dorsal hippocampus and consisted of seizure activity that began in the hippocampus and spread rapidly to the occipital cortex. This activity lasted 20-30 s, and during this period the rats presented immobility. During the first 40-50 min after its administration, three to four other similar short EEG seizure periods occurred and the rats presented the following behavioral alterations: akinesia, facial automatisms, head tremor, salivation, rearing, jumping, barrel-rolling, wet dog shakes and forelimb clonic movements. Within 40-50 min, the status epilepticus was established and lasted 8-12 h. These results are similar to those observed in the acute phase of the pilocarpine model of temporal lobe epilepsy and suggest that granulitoxin may be a useful tool not only to study the sodium channels, but also to develop a new experimental model of status epilepticus.Universidade Estadual do Ceará Departamento de Ciências Fisiológicas Laboratório de NeurofarmacologiaUniversidade Federal de São Paulo (UNIFESP) Departamento de Neurologia e Neurocirurgia Laboratório de Neurologia ExperimentalUniversidade de Brasília Departamento de Biologia Celular Centro Brasileiro de Serviços e Pesquisas em ProteínasUNIFESP, Depto. de Neurologia e Neurocirurgia Laboratório de Neurologia ExperimentalSciEL

    Carcass characteristics and meat quality of lambs fed high levels of spineless cactus in the diet

    Get PDF
    The objective was to evaluate the effect of increasing the dietary inclusion of spineless cactus (Nopalea cochenillifera Salm Dyck) on the carcass characteristics and meat quality of confined lambs. Thirty-two male Santa Inês lambs with an average age of 140 days and an initial body weight of 20.4 ± 2.60 kg were used in this study. The lambs were housed in individual stalls for 70 days and individually fed a ration with spineless cactus included at 0, 241, 519, or 753 g/kg of dry matter (DM). The lambs were slaughtered, and characteristics of the carcass and meat were recorded and analysed. Inclusion of spineless cactus had a quadratic effect on the bodyweight at slaughter and on the empty bodyweight of the lambs. The inclusion of 500 g/kg of spineless cactus provided the highest predicted cold carcass weight (16.03 kg). There was a quadratic effect of the inclusion of spineless cactus on the weight of meat cuts and leg composition of lambs. The inclusion of spineless cactus did not influence pH, tenderness, and water-retention capacity of the meat. However, the intramuscular fat content increased 1 mg for every 10 g/kg inclusion of spineless cactus in the diet. Quadratic effects were observed of the inclusion of spineless cactus on the weights of the liver, heart, rumen, blood, skin and internal fat of the lambs. Up to 500 g/kg of spineless cactus could be included in the diet of confined lambs

    Wild Roman chamomile extracts and phenolic compounds: enzymatic assays and molecular modelling studies with VEGFR-2 tyrosine kinase

    Get PDF
    Angiogenesis is a process by which new blood vessels are formed from the pre-existing vasculature, and it is a key process that leads to tumour development. Some studies have recognized phenolic compounds as chemopreventive agents; flavonoids, in particular, seem to suppress the growth of tumor cells modifying the cell cycle. Herein, the antiangiogenic activity of Roman chamomile (Chamaemelum nobile L.) extracts (methanolic extract and infusion) and the main phenolic compounds present (apigenin, apigenin-7-O-glucoside, caffeic acid, chlorogenic acid, luteolin, and luteolin-7-O-glucoside) was evaluated through enzymatic assays using the tyrosine kinase intracellular domain of the Vascular Endothelium Growth Factor Receptor-2 (VEGFR-2), which is a transmembrane receptor expressed fundamentally in endothelial cells involved in angiogenesis, and molecular modelling studies. The methanolic extract showed a lower IC50 value (concentration that provided 50% of VEGFR-2 inhibition) than the infusion, 269 and 301 μg mL(-1), respectively. Regarding phenolic compounds, luteolin and apigenin showed the highest capacity to inhibit the phosphorylation of VEGFR-2, leading us to believe that these compounds are involved in the activity revealed by the methanolic extract.The authors are grateful to strategic projects PEst-OE/AGR/UI0690/2014 and PEst-C/QUI/UI0686/2013-2014 for financial support to the research centres. R. Guimarães, and R. Calhelha thank to FCT, POPH-QREN and FSE for their grants (SFRH/BD/78307/2011 and SFRH/BPD/68344/2010)

    Crataegus monogyna buds and fruits phenolic extracts: growth inhibitory activity on human tumor cell lines and chemical characterization by HPLC–DAD–ESI/MS

    Get PDF
    Crataegus monogyna has been extensively studied due to its various alleged health benefits. This study aimed to determine the human tumor cells growth inhibitory activity of phenolic extracts of its flower buds and fruits in three phenological stages, and further characterize the extracts by HPLC–DAD–ESI/MS. Flower bud extract showed the highest antiproliferative activity as indicated by the lowest GI50 values obtained in all the tested cell lines: MCF-7, breast adenocarcinoma; NCI-H460, non-small cell lung cancer; HeLa, cervical carcinoma; HepG2, hepatocellular carcinoma. Furthermore, porcine liver primary cell culture (PLP2) was used to evaluate toxicity to non-tumor cells. Flavonoids, particularly flavonols and flavones (higher in flower buds) and proanthocyanidins (higher in unripe fruits) were the main classes in the studied samples. Phenolic acids (mainly hydroxycinnamic acid derivatives) were also detected in significant amounts, especially in flower bud extract. Regarding anthocyanins, over ripened fruits gave the highest content. The higher bioactivity observed in flower buds might be related with its higher content in phenolic compounds

    Autopoiesis in creativity and art

    Get PDF
    The term autopoiesis, (meaning ‘self’) and ‘poiesis’ (mean- ing ‘creation, production’) defines a system capable of repro- ducing and maintaining itself. The term was introduced by the theoretical biologists, Humberto Maturana and Francisco Varela, in 1972 to define the self-maintaining chemistry of living cells. The term has subsequently also been applied to the fields of systems theory and sociology. In this paper we apply this model to characterise creativity in art practise
    • …
    corecore